Temperature monitoring devices for electrical apparatus, switchgears with same and related methods

ABSTRACT

Temperature monitoring devices have a primary body with an inner circular perimeter, a temperature monitoring segment held by the primary body, the temperature monitoring segment comprising an inwardly extending thermal probe, and a fastener assembly segment held by the primary body at a location that is circumferentially spaced apart from the temperature monitoring segment. The fastener assembly segment has a circumferentially extending bracket that can be radially extended in a direction that is toward the inner circular perimeter of the device.

FIELD OF THE INVENTION

The present disclosure relates to temperature sensor assembliesparticularly suitable for switchgears.

BACKGROUND OF THE INVENTION

Known temperature monitoring devices on the market today are mostlycircular. That means the devices encircle the contacts to measure thetemperature of the certain points inside a device such as a switchgearcabinet.

FIG. 1A, FIG. 1B and FIG. 1C illustrate a conventional temperaturemonitoring device. The device includes a current transformer (CT) coil11 with an iron core for energy harvesting and a main body of themeasuring device 12. The device also includes a thermal sensor 13 suchas a digital wireless thermal sensor and a printed circuit board (PCB)14 with a processor and wireless chip. The temperature measurementdevice can have an inner perimeter extending about a circular opencenter aperture 15 that receives/encircles a contact of an electricalapparatus such as a switchgear. The entire circumference of the contactis covered by the inner perimeter of the device which can result in poorheat dissipation performance.

Also, the conventional temperature monitoring device has two fasteningscrews to affix itself to the contact and the sensor probe is fixed tothe inner perimeter circle and can't be adjusted. As a result, thesensor probe may not be properly positioned because of manufacturingvariabilities. Thus, the sensor probe may not touch the contact surfacethoroughly which can also influence the measurement accuracy and/orperformance.

SUMMARY OF EMBODIMENTS OF THE INVENTION

Embodiments of the present invention provide devices that allow improvedinstallation methods which ensure a robust touch between a thermal probeand a target contact which can also avoid or reduce heat dissipationperformance degradation.

Embodiments of the invention provide a fastener assembly with a gearstructure for fastening the temperature monitoring device to a contact.

Embodiments of the invention provide an adjustment assembly with adouble-adjustable structure for a sensor probe to cause the sensor probeto abut a contact surface.

Embodiments of the invention can improve heat dissipation performanceusing a gear structure.

Embodiments of the invention provide small adjacent convexly curvedmembers on an inner facing perimeter to reduce a contact area with thetarget contact.

Embodiments of the invention are directed to temperature monitoringdevices. The devices include: a primary body with an inner circularperimeter and a temperature monitoring segment held by the primary body.The temperature monitoring segment has an inwardly extending thermalprobe. The device also includes a fastener assembly segment held by theprimary body at a location that is circumferentially spaced apart fromthe temperature monitoring segment. The fastener assembly segment has acircumferentially extending bracket that can be radially extended in adirection that is toward the inner circular perimeter of the device.

The temperature monitoring segment can have first and second inwardlyprojecting members, one on each side of the thermal probe.

The first and second projecting members comprise an elastic material,optionally with chamfered edges and/or a convexly curved inner facingsurface.

The first and second projecting members are at least one of flexible orcomprise an elastic material.

The first and second projecting members can optionally be compressibleso as to be able to compress radially outward in a range between 1-20%in response to a force applied during installation to a target contact.

The temperature monitoring segment can also include an inner shellholding a digital wireless temperature sensor that is attached to theprobe and an outer shell that encloses the inner shell. The outer shellcan have a radially inwardly extending bracket that encloses a length ofa leg of the thermal probe that extends between the temperature sensorand the thermal probe. The segment can also include at least one innerresilient member residing between the inner shell and the outer shelland at least one outer resilient member residing between the outer shelland an outer perimeter of the temperature monitoring device. Duringinstallation and application of a force onto the thermal probe, the atleast one inner resilient member can compress so that the inner shellmoves relative to the outer shell to retract the probe against a distalend of the bracket and the at least one outer resilient member cancompress when the inner and outer shell move together radially outwardtoward the outer perimeter of the device.

The at least one inner resilient member can be provided as first andsecond spaced apart leaf springs.

The at least one outer resilient member can be a single leaf spring heldin a shaped cavity of a housing member of the temperature monitoringsegment.

The device can have an inner open circular channel and an outer circularperimeter. The primary body can have a longitudinal extent that is lessthan a longitudinal extent of the temperature monitoring segment and thefastener assembly segment to thereby provide ventilation spaces.

The bracket can have an arcuate inwardly facing surface with a radius ofcurvature corresponding to a radius of the inner circular perimeter ofthe device.

The bracket can have a threaded center channel that receives a threadedbolt.

The fastener assembly segment can have a first gear that cooperates witha second gear that can move the fastener bracket.

The first gear can be a worm gear and the second gear can be a wheelgear. The wheel gear can be attached to a threaded bolt that extendsinto a threaded channel of the bracket to translate the bracket radiallyin response to rotation of the wheel gear by the worm gear.

The worm gear can have an outer facing end with a slot for a user toaccess to turn the worm gear and adjust a position of the bracket.

A medial location of the bracket of the fastener assembly segment can bediametrically opposed to the thermal probe.

Other embodiments are directed to switchgears. The switchgears have atleast one temperature monitoring device and at least one contact thatextends through an open circular channel of a respective temperaturemonitoring device. The temperature monitoring device includes a primarybody comprising an inner circular perimeter and a temperature monitoringsegment held by the primary body. The temperature monitoring segment hasan inwardly extending thermal probe. The temperature monitoring segmenthas first and second projecting members, one on each side of the thermalprobe. The temperature monitoring device also includes a fastenerassembly segment held by the primary body at a location that iscircumferentially spaced apart from the temperature monitoring segment.The fastener assembly segment includes a circumferentially extendingbracket that can be radially extended in a direction that is toward theinner circular perimeter of the device.

The first and second projecting members may have a convexly curved innerfacing surface.

The temperature monitoring segment can further include an inner shellholding a digital wireless temperature sensor that is attached to theprobe and an outer shell that encloses the inner shell. The outer shellcan have radially inwardly extending bracket. The bracket can enclose alength of a leg of the thermal probe that extends between thetemperature sensor and the thermal probe. The temperature monitoringsegment can also have at least one inner resilient member residingbetween the inner shell and the outer shell and at least one outerresilient member residing between the outer shell and an outer perimeterof the temperature monitoring device. During installation andapplication of a force onto the thermal probe, the at least one innerresilient member can compress so that the inner shell moves relative tothe outer shell to retract the probe against a distal end of thebracket. The at least one outer resilient member can compress when theinner and outer shell move together radially outward toward the outerperimeter of the device.

The fastener assembly segment can include a worm gear attached to awheel gear. The wheel gear can be attached to a threaded bolt thatextends into a threaded channel of the bracket to translate the bracketradially in response to rotation of the wheel gear by the worm gear. Amedial location of the bracket of the fastener assembly segment can bediametrically opposed to the thermal probe.

Yet other embodiments are directed to methods of installing atemperature monitoring device into a switchgear. The methods include:(a) providing a temperature monitoring device with an open centerchannel, a fastener assembly segment and a spaced apart temperaturemeasuring segment, the temperature measuring segment including a thermalprobe; (b) placing the temperature monitoring device about acircumference of a contact of a switchgear so that the contact extendsthrough the open center channel; (c) radially advancing acircumferentially extending bracket of the fastener assembly toward thecontact to align the device with an outer surface of the contact; and(d) compressing at least one (typically a plurality) resilient member ofthe temperature measurement segment to retract the thermal probe againsta bracket while an exposed end of the probe touches the outer surface ofthe contact.

The device can have a primary body with ventilation gap spaces extendingangularly between 30-90 degrees between the temperature monitoringsegment and the fastener assembly segment which can vent heat and reduceheat dissipation performance degradation.

The temperature monitoring segment can include an outer shell enclosingan inner shell holding a bracket that encloses a length of a legextending between a primary body of the temperature sensor and thethermal probe and with at least one resilient member between the outershell and the inner shell and the compressing can include firsttranslating the probe to contact an end of the bracket, then translatingthe inner and outer shells concurrently to compress an outer resilientmember; and/or the temperature monitoring segment can comprise first andsecond outwardly extending members, one on each side of the temperatureprobe that touch the outer surface of the contact and these member mayfurther optionally have convex curved surfaces.

Further features, advantages and details of the present invention willbe appreciated by those of ordinary skill in the art from a reading ofthe figures and the detailed description of the preferred embodimentsthat follow, such description being merely illustrative of the presentinvention.

It is noted that aspects of the invention described with respect to oneembodiment, may be incorporated in a different embodiment although notspecifically described relative thereto. That is, all embodiments and/orfeatures of any embodiment can be combined in any way and/orcombination. Applicant reserves the right to change any originally filedclaim or file any new claim accordingly, including the right to be ableto amend any originally filed claim to depend from and/or incorporateany feature of any other claim although not originally claimed in thatmanner. These and other objects and/or aspects of the present inventionare explained in detail in the specification set forth below.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a back view of a prior art temperature measuring device.

FIG. 1B is a front view of the prior art device shown in FIG. 1A.

FIG. 1C is a side view of the device shown in FIGS. 1A and 1B.

FIG. 2A is a front view of a temperature measuring device according toembodiments of the present invention.

FIG. 2B is a back view of the device shown in FIG. 2A.

FIG. 2C is a side view of the device shown in FIGS. 2A and 2B.

FIG. 3A is a front view of the device shown in FIG. 2A but with a coverplate omitted to illustrate a fastener structure according toembodiments of the present invention.

FIG. 3B is an enlarged partial front view of the device shown in FIG. 3Aillustrating the fastener assembly according to embodiments of thepresent invention.

FIG. 4 is an enlarged side perspective view of the fastener assemblyshown in FIG. 3B.

FIG. 5A is a front view of the device shown in FIG. 2A but with a coverplate omitted to illustrate a temperature measurement segment accordingto embodiments of the present invention.

FIG. 5B is an enlarged partial front view of the device shown in FIG. 5Aillustrating the at least one inwardly projecting member of thetemperature measurement segment according to embodiments of the presentinvention.

FIG. 5C is a greatly enlarged partial front view of a portion of thetemperature measurement segment (shown without the temperature probe ortemperature sensor) according to embodiments of the present invention.

FIG. 5D is a greatly enlarged schematic illustration of an inwardlyprojecting member with according to embodiments of the presentinvention.

FIG. 6 is an enlarged front view of the adjustment assembly shown inFIG. 5B.

FIG. 7A-FIG. 7C illustrate exemplary different radial positionaladjustment states of the temperature probe held by the adjustmentassembly shown in FIG. 6 according to embodiments of the presentinvention.

FIG. 8A and FIG. 8B are front views of the temperature measuring deviceshowing different relative positions of components using the fastenerassembly and adjustment assembly according to embodiments of the presentinvention.

FIGS. 9-12 are schematic illustrations of a force analysis of a leafspring according to embodiments of the present invention.

FIG. 13 is a schematic illustration of a switchgear with at least oneonboard temperature monitoring device such as that shown in FIGS. 2A-2C,for example, according to embodiments of the present invention.

FIG. 14 is a flow chart of actions that can be used to assemble and/oradjust a temperature sensor relative to a target contact according toembodiments of the present invention.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION

The present invention now will be described more fully hereinafter withreference to the accompanying drawings, in which illustrativeembodiments of the invention are shown. Like numbers refer to likeelements and different embodiments of like elements can be designatedusing a different number of superscript indicator apostrophes (e.g., 10,10′, 10″, 10′″). The terms “Fig.” and “FIG.” may be used interchangeablywith the word “Figure” as abbreviations thereof in the specification anddrawings. In the figures, certain layers, components or features may beexaggerated for clarity, and broken lines illustrate optional featuresor operations unless specified otherwise.

In the drawings, the relative sizes of regions or features may beexaggerated for clarity. This invention may, however, be embodied inmany different forms and should not be construed as limited to theembodiments set forth herein; rather, these embodiments are provided sothat this disclosure will be thorough and complete, and will fullyconvey the scope of the invention to those skilled in the art.

It will be understood that, although the terms first, second, etc. maybe used herein to describe various elements, components, regions, layersand/or sections, these elements, components, regions, layers and/orsections should not be limited by these terms. These terms are only usedto distinguish one element, component, region, layer or section fromanother region, layer or section. Thus, a first element, component,region, layer or section discussed below could be termed a secondelement, component, region, layer or section without departing from theteachings of the present invention.

Spatially relative terms, such as “beneath”, “below”, “lower”, “above”,“upper” and the like, may be used herein for ease of description todescribe one element or feature's relationship to another element(s) orfeature(s) as illustrated in the figures. It will be understood that thespatially relative terms are intended to encompass differentorientations of the device in use or operation in addition to theorientation depicted in the figures. For example, if the device in thefigures is turned over, elements described as “below” or “beneath” otherelements or features would then be oriented “above” the other elementsor features. Thus, the exemplary term “below” can encompass both anorientation of above and below. The device may be otherwise oriented(rotated 90° or at other orientations) and the spatially relativedescriptors used herein interpreted accordingly.

The term “about” refers to numbers in a range of +/−20% of the notedvalue.

As used herein, the singular forms “a”, “an” and “the” are intended toinclude the plural forms as well, unless expressly stated otherwise. Itwill be further understood that the terms “includes,” “comprises,”“including” and/or “comprising,” when used in this specification,specify the presence of stated features, integers, steps, operations,elements, and/or components, but do not preclude the presence oraddition of one or more other features, integers, steps, operations,elements, components, and/or groups thereof. It will be understood thatwhen an element is referred to as being “connected” or “coupled” toanother element, it can be directly connected or coupled to the otherelement or intervening elements may be present. As used herein, the term“and/or” includes any and all combinations of one or more of theassociated listed items.

Unless otherwise defined, all terms (including technical and scientificterms) used herein have the same meaning as commonly understood by oneof ordinary skill in the art to which this invention belongs. It will befurther understood that terms, such as those defined in commonly useddictionaries, should be interpreted as having a meaning that isconsistent with their meaning in the context of this specification andthe relevant art and will not be interpreted in an idealized or overlyformal sense unless expressly so defined herein.

Embodiments of the invention are particularly suitable for electricalpower distribution devices such as switchgears. As employed herein theterm “switchgear” includes, but is not be limited to, a circuitinterrupter, such as a circuit breaker (e.g., without limitation,low-voltage, medium-voltage or high-voltage), a motorcontroller/starter, and/or any suitable device which carries ortransfers current from one place to another.

As employed herein the term “power bus” shall expressly include, but notbe limited by, a power conductor, a power bus bar, and/or a power busstructure for a circuit interrupter.

The present invention is described in association with a temperaturemonitoring device for a contact or other cylindrical conductor of aswitchgear, although the invention can be applicable to a wide range ofproducts.

FIGS. 2A-2C illustrate a temperature monitoring device 10 according toembodiments of the present invention. The device 10 has a primary body21 with a circular inner perimeter 127 p enclosing an open centeraperture or channel 27. As shown, the device 10 may also have a circularouter perimeter 128 p. A target contact (82, FIG. 8) for temperaturemeasurement can extend through the channel 27. The device 10 cancomprise or cooperate with a current transformer (CT) coil with a core25 for energy harvesting. The device 10 can also include at least oneinwardly projecting member 26, typically a plurality of members 26 shownas two, adjacent members 26. The at least one inwardly projecting member26 can support the device 10 and reduce abutting contact surface areabetween the temperature measuring device 10 and a surface of a targetcontact.

The device 10 has a temperature measuring segment 22 with a temperatureprobe 55 (also interchangeably called a “thermal probe”) and anadjustable assembly 122 shown inside a cover plate 22 c in FIGS. 2A and2C, for example. The sensor probe 55 abuts (i.e., touches) a surface ofa target contact to measure the temperature. The thermal probe 55 canreside between neighboring inwardly projecting members 26. The thermalprobe 55 can be attached to or an integral component of a thermal sensor52 (FIGS. 5A, 5B) which can be a wireless digital thermal sensor such aspart number DS18B20 from Maxim Integrated, San Jose, Calif. As employedherein, the term “wireless” means without a hard-wired or physicalconnection, without an electrical conductor and without an optical fiberor waveguide.

The at least one inwardly projecting member 26 can have a width W₁ thatis greater than a width W₂ of the temperature probe 55, typicallybetween 25%-200% the width of the temperature probe 55 as shown in FIGS.5C, 5D and 6. The at least one inwardly projecting member 26 can projecta distance forward of the inner perimeter 127 p of the device 10. Theinnermost edge of the probe 55 i and the innermost edge of 26 i of theat least one inwardly projecting member 26 can reside at the same radiusR2 (FIG. 5C).

Referring to FIGS. 5C and 5D, the inwardly projecting member 26 can havea convexly curved shape such that the member 26 curves outward towardthe center channel 27 and may have a radius of curvature R2corresponding to the contact 82 (FIG. 13) to support the device 10. Theinwardly projecting member 26 can comprise an elastic material, such asrubber.

Referring to FIG. 5D, the at least one inwardly projecting member 26 canhave a width in a range of about 4 mm to about 8 mm and a height(projecting distance) in a range of 1.2 mm to about 3 mm.

During the assembling process, the device 10 can be fastened to thecontact 82 (FIG. 8A) with the fastener assembly 24 comprising thecooperating gears. The contact 82 can be pressed to/against the at leastone inwardly projecting member 26. The at least one inwardly projectingmember can be one or more of resiliently configured, flexible, elasticand/or compressible with a degree of compression in a range of about1%-20%, typically in a range of 5%-20% upon an applied contact forcewith the contact 82, and is more typically compressible 15% or less,such as 15%, 14%, 13%, 12%, 11%, 10%, 9%, 8%, 7%, 6%, and 5%, forexample, to avoid inadvertent damage to the at least one inwardlyprojecting member 26.

Referring to FIGS. 5B and 5C, the at least one inwardly projectingmember 26 can be convex to support the device 10. However, the at leastone inwardly projecting member 26 can have other shapes such as a planarshape. The at least one inwardly projecting member 26 can have a radiusof curvature R2 that is less than R1, which correspond to neighboringsegments of the inner perimeter of the device 10, measured from thecenter of the circular inner perimeter of the primary body of thedevice.

FIG. 5D, for example, illustrates that the at least one projectingmember 26 can have outer edges 26 e that are rounded (i.e., shaped asfillets). The inwardly projecting member 26 can be rectangular with achamfer or rounding of exterior corners.

As shown in FIGS. 2A, 2B and 2C, the device 10 can also include afastener assembly 24 that is positioned at a circumferentially spacedapart segment away from the temperature measuring segment 22. As shown,the fastener assembly 24 diametrically opposes the temperature segment22.

Referring to FIGS. 3A, 3B, and 4, the fastener assembly 24 can include acircumferentially extending bracket 32 and cooperating gears 33, 34. Thegears 33, 34 can also reside inside a respective cover plate 24 c (FIGS.2A, 2C).

Referring to FIG. 2C, the primary body 21 can have a circular shape. Theprimary body 21 can have a longitudinal (axially extending) dimension d₁that is less than a longitudinal (axially extending) dimension d₂ of thefastener assembly 24 and the adjustment assembly 22. Stated differently,the temperature measuring segment 22 and the fastener assembly segment24 both have a greater extent in the longitudinal (axial) direction thanthe primary body 21, typically 2×-10× greater.

The primary body 21 can have a disk shaped support base 21 b with anopen center 27 that has diametrically opposed outer perimeter arms 121that extend a distance forward of the base 21 b. The arms 121 can bearcuate and extend for a sub-length of the circumference to span only arespective outer perimeter of the fastener assembly 24 and theadjustment assembly 22. As shown in FIGS. 2A and 2C, the primary body 21can provide ventilation and/or recess spaces 30 that are longitudinallyspaced apart a distance from a surface of the target contact so that thedevice 10 does not contact the target contact its entire circumferenceas does the device and primary body 12 of the prior art device (FIG.1C).

Referring to FIGS. 3A, 3B and 4, the fastener assembly 24 is shownaccording to embodiments of the present invention. The fastener assembly24 includes cooperating gears 33, 34. As shown, the cooperating gears33, 34 can include a worm gear 34 that engages an adjacent wheel gear 33that is attached to the bracket 32. The bracket 32 can move radially,i.e., extend and/or retract in response to input from the gears 33, 34.

The bracket 32 can have an inner surface 32 i that is arcuate, typicallywith a radius of curvature that corresponds to the inner perimeter 127 pand/or target contact 82 (FIGS. 8A, 8B). The bracket 32 can be attachedto and move relative to a housing member 31 that can be attached to theprimary body 21 of the measuring device 10. The inner surface 32 i ofthe bracket 32 will touch the contact surface 82 s (FIG. 8B) avoidingthe contact 82 (FIGS. 8A, 8B) from touching the remainder of a lowercircle inner surface of underlying part of the temperature segment 22and/or arm 121.

Referring to FIG. 3A, the fastener assembly bracket 32 can have acircumferential extent or angle “α” that is between 30-90 degrees,typically between about 45 to about 75 degrees, inclusive thereof.

The worm gear 34 can rotate the gear wheel 33 to extend or retract thebracket 32. Thus, a user can fasten the bracket 32 into a desiredposition relative to the contact surface 82 s (FIGS. 8A, 8B) by rotatingthe worm gear 34 via the screw slot 34 s.

Referring to FIG. 3B, the fastener assembly 24 can include a pair ofplanar plates 35 that hold the gear wheel 33 and the worm gear 34therebetween, attached to the housing member 31.

The dimensions of the gear wheel 33 and worm gear 34 are closely relatedwith the size of the primary body 21 and the angle α in FIG. 3A. Forexample, in some embodiments, according to the angle α range 30˜90degrees, the range of the outer diameter of the gear wheel 33 is about 5mm to about 12 mm and the size of the worm gear 34 matably engages thechosen gear wheel 33. The gears 33, 34 can comprise any suitablematerial and can be electrically and/or thermally insulating, at leastheat-resistant with sufficient strength. One example of a suitablematerial is phenolic resin. The bracket 32 can comprise any suitablematerial, and is also preferably electrically insulating andheat-resistant with sufficient strength, although metal is not preferredand may comprise phenolic resin. The bracket 32 can have the same or adifferent material from the primary body 21 of the device 10.

In some embodiments, the term “heat resistant” means that the materialcan withstand operating temperatures of at least 55 degrees C. for adesired shelf life (typically up to about 150 degrees C.) without unduedegradation so as to maintain its shape and function. In someembodiments, the term “heat resistant” includes sub-zero temperatures.In some embodiments, the term “heat resistant” includes operatingtemperatures between −55 degrees C. and 150 degrees C. The projectingmember 26 can be heat resistant and comprise EPDM(Ethylene-Propylene-Diene Monomer).

Referring to FIG. 4, the gear wheel 33 can be attached to or include ascrew bolt 37 which rotates together with the gear wheel 33. The bolt 37cooperates with a threaded channel 32 c in the bracket 32 and transmitsthe rotation motion to linear motion so the bracket 32 can move tofasten the device 10 in position.

FIGS. 5A, 5B, 5C and 6 illustrate a temperature measuring segment 22 ofthe device 10. The temperature measuring segment 22 can comprise adouble-adjustable structure of the thermal probe 55. The segment 22 caninclude a housing member 51 that is attached to the primary body 21 ofthe device 10. The housing member 51 can hold a primary body 52 b of atemperature sensor 52. The primary body 52 b of the temperature sensor52 can comprise the thermal sensor 52, a processor 52 p and a wirelesscommunication chip 52 c, typically enclosed an on a printed circuitboard 52 p. The segment 22 can also comprise at least one resilientmember 53, shown as at least one leaf spring 53. The at least oneresilient member 53 can be curved in a direction that faces the outerperimeter 128 p of the device 10. The bracket 54 can reside in a channel51 c in the housing member 51.

A medial location of the bracket 32 of the fastener assembly segment 24can be diametrically opposed to the thermal probe 55 as shown in FIG.5A.

The thermal probe 55 and the primary body 52 b of the sensor 52 canradially extend and retract as a unit relative to the inner perimeter ofthe device 10.

When the inner housing 65 with the temperature sensor 52 moves radiallyoutward (shown as upward in the orientation shown), it can compress theat least one resilient inner member 63 and/or outer resilient member 53and provide an opposing force to the sensor probe 55 to ensure a firmand/or thorough abutment (touching) of the sensor probe 55 to thecontact 82 (FIG. 8).

The housing member 51 can include a shaped cavity 122 (FIG. 5B, 6,7A-7C) that holds the sensor body 52 b and resilient member 53. Thehousing member 51 can also provide the at least one projecting member 26to be adjacent the probe 55. The at least one projecting member(s) 26can be held in a fixed position.

As shown in FIGS. 5B, 5C and 6, the at least one projecting member 26can be two adjacent members 26 separated by an open housing channel 51 cthat slidably receives the temperature probe 55 and/or leg 55 s thereof.

FIGS. 5B and 6 shows an outer portion 510 portion of the housing 51 andthe shaped cavity 122 holding the at least one resilient member 53therein. The shaped cavity 122 has an outer wall 122 w that is in astatic or fixed position. The shaped cavity 122 has an outer portionthat faces the outer perimeter 128 p of the device 10. The housing 51can hold an outer shell (which can also be called a case) 61 that holdsan inner shell (that can also be called a case) 65, each forward of theat least one resilient member 53. The outer and inner shells 61, 65 canmove radially relative to the housing 51. The inner shell 65 holds thetemperature sensor 52. The outer shell 61 holds the inner shell 65 andat least one inner resilient member 63, shown as first and second spacedapart inner leaf springs 63, between the inner shell 65 and an adjacentinner surface 61 i of a wall 61 w of the outer shell 61.

While the at least one resilient member 53 and/or 63 may comprise one ormore leaf springs, other resilient members can be used. For example,Belleville springs, singular or stacked, coil springs, clover springs,or any other type of flexible elastic member or spring memory deviceincluding, for example, elastomeric O-rings, flexible washers or plugsand the like to provide a desired spring force. Combinations ofdifferent components can be used.

The temperature probe 55 can be attached to an intermediate leg orextension segment 55 s that connects and extends between the primarybody of the sensor 52 b and the external probe 55. In a non-loadedconfiguration, the end of the segment 55 e and the probe 55 can extendoutside the bracket 54 as shown in FIG. 6. In some embodiments, thedistance between the temperature probe 55 and the bracket 54 in a fullextension (non-loaded) position is 0 (if the manufacturing tolerancesallow) to about 0.8 mm (limited by the structure of some embodiments).The bracket 54 can be a monolithic component of the outer shell 61. Thebracket 54 can be elongate and may have any suitable shape such as, butnot limited to, cylindrical, rectangular or planar or have any othershape.

The sensor probe 55 and intermediate leg 55 s can be linked with the PCB52 p, and the PCB 52 p is inside the inner shell 65 (FIG. 5B, 6). So thethermal probe 55, the intermediate leg 55 s, PCB 52 p and inner shell 65can move together and relatively with the bracket 54 and outer shell 61.The bracket 54 can be elongate. If so, the distance between the probe 55and bracket 54 can meet the dimensional spacing described above.

The at least one inner resilient member 63 can comprise first and secondleaf springs 63 that can be laterally spaced apart and positioned onopposing end portions of the primary body 52 b of the sensor 52 and canextend between the primary sensor body 52 b and the at least oneresilient member 53.

The temperature monitoring segment 22 can have a double-adjustablestructure, with a primary adjustable structure 22 p with the at leastone resilient member 53 and a secondary adjustable structure that 22 scomprises the at least one inner resilient member 63. The primaryadjustment structure 22 p allows for movement of the inner shell 65 withthe probe 55 and sensor body 52 b relative to the outer perimeter 128 pof the device 10. The secondary adjustment structure 22 s allows theprobe 55 to retract relative to the bracket 54.

The sensor probe 55 may be structurally weak and may, without support,not be able to endure the force from contact with the contact 82 (FIG.8A) when fastening. The bracket 54 in the housing member 51 can protectthe sensor probe 55 from direct force. However, due to typicalmanufacturing variances, the bracket 54 may be sized with a shorterlength than the length of the probe between the primary body 52 b andthe probe 55. A secondary adjustable structure 22 s can be employed andused with the bracket 54. Upon a first force from engagement with acontact, the inner shell 65 can be compressed firstly until the sensorprobe 55 touches the bracket 54, and then the outer shell 61 iscompressed with the bracket 54 enduring the force. So, the inner leafsprings 63 are designed to be much weaker than the outer resilientmember 53, which can be a leaf spring. As a result, the sensor probe 55can be protected.

FIG. 7A, FIG. 7B, and FIG. 7C illustrate three representative positionalstates of the probe 55. The three parallel dashed/broken lines are thelines to describe the three relative operational positions. The outerdashed line represents the outer perimeter of the device 128 p havingthe cavity 122 and this distance is constant and fixed. The intermediateline represents a location of the wall 61 w of the outer shell in afully extendable location relative to the outer perimeter 128 p of theprimary adjustable structure 22 p and the lower line represents theforwardmost position of the probe 55 allowed by the secondary adjustablestructure 22 s.

FIG. 7A illustrates an original state and/or position where both theprimary and secondary adjustable structures 22 p, 22 s are in arespective bottom (radially forward) position with a distance Dmaxbetween the outer perimeter 128 p of the device 10 and the tip of theprobe 55 i. The sensor probe 55 is also in its fully extended state andthe sensor bracket 54 is spaced apart from the sensor probe 55 with agap space 54 g therebetween.

FIG. 7B illustrates a first compression state and/or position where onlythe secondary adjustable structure 22 s is compressed as the at leastone inner resilient member 63 (i.e., leaf springs) is compressed. The atleast one inner resilient member 63 (i.e., leaf springs) has a smallerspring force F1 (i.e., is much weaker) than the spring force F2 appliedby the outer resilient member 53, so the primary adjustable structure 22p with the outer resilient member 53 is not compressed or is partiallycompressed. F2 can be 2-10× greater than F1, more typically 3×-4×greater than F1, in some embodiments. In some particular embodiments, F1is about 3-4 N and F2 is about 10-12 N. As shown, the sensor probe 55retracts and touches the sensor bracket 54. The bracket 54 can fullyprotect the sensor probe 55 from undue contact force.

FIG. 7C illustrates a second compression state and/or position. Theprimary adjustable structure 22 p is further compressed relative toeither of the first and second states. At this time, the primary andsecondary adjustable structures 22 p, 22 s and/or the inner and outershells 61, 65 can move together to an end position. Thus, the sensorprobe 55 can be protected.

FIG. 8A and FIG. 8B illustrate a comparison of the device 10 before andafter fastening to the contact 82. A circumferential outline of thecontact surface 82 s is shown with respect to the inner perimeter 127 pof the device 10. As shown, two inwardly projecting members 26 extendingfrom the inner perimeter 127 p can be applied to support the contact 82and reduce an area associated with abutting or touching area. Thebracket 32 of the fastener assembly 24 can adjust the position of thetemperature monitoring segment 22 so that the device 10 places thecenter channel or aperture 27 to be concentric with the contact 82.

FIG. 8A illustrates an initial position and orientation during assemblyor installation of the temperature monitoring device 10 to the contact82. FIG. 8B is an example of a suitable assembled state when thefastener assembly 24 is adjusted using the cooperating gears 33, 34 andthe bracket 32 and with the primary and secondary adjustment structures22 p, 22 s compressed.

As shown in FIG. 8B, the only physical contact (touching parts) betweenthe device 10 and the contact 82 are the two projecting members 26, thetemperature probe 55 and the fastening bracket 32 greatly reducing thetouching area relative to the device shown in FIGS. 1A-1C. This providesa gap or ventilation space 30 over an angular distances β₁, β₂ on eachside of the device 10 between the temperature monitoring segment 22 andthe fastener assembly 24. The angular distances β₁, β₂, can be the sameor different and are typically each between 30 and 90 degrees.

Out of completeness, a discussion on forces chosen for the resilientmembers 53, 63 is provided below using the example of leaf springs.However, it will be appreciated by one of skill in the art that similarrationales and calculations may be used for other resilient memberconfigurations and/or types. Furthermore, this discussion is by way ofexample only as different devices may have different size and forcerequirements/considerations.

With respect to the inner leaf spring(s) 63, the resistant force shouldnot be too large as excessive force may be loaded to the sensor probe 55which may cause damage. Also, the force provided by the inner leafspring(s) 63 should be smaller than that of the outer one 53. Otherwise,the outer shell 61 can move before the inner shell 65 which may resultin a loss of a sensor-protecting function by the shaft 54.

To calculate the leaf spring size, a relationship between the load and acompressed distance can be constructed. First, a simplified model of aforce analysis for a leaf spring is shown in FIG. 9.F ₁=2F ₂  Equation 1The diagram can be simplified to half as shown on the right side of FIG.9.

$\begin{matrix}{\frac{F_{1}}{2} = F_{2}} & {{Equation}\mspace{14mu} 2}\end{matrix}$Half of a leaf spring can be equivalent to a pressed cantilever as shownin FIG. 10. For a cantilever, the end deflection y can be calculated byEquation 3.

$\begin{matrix}{y = \frac{{Fl}^{3}}{3{EI}}} & {{Equation}\mspace{14mu} 3}\end{matrix}$Where F is the end load, l is the length of the beam, E is the elasticmodulus of the material and I is the moment of inertia of the section.Thus, force can be expressed by Equation 4.

$\begin{matrix}{F = \frac{3{EIy}}{l^{3}}} & {{Equation}\mspace{14mu} 4}\end{matrix}$This can be simplified to Equation 5.F=f(y)  Equation 5In this situation, the load process of the half leaf spring is contraryto that of cantilever. For the cantilever, it's assumed that with thedeflection y₀, the load F₀ is expressed by Equation 6.

$\begin{matrix}{F_{0} = \frac{3{EIy}_{0}}{l^{3}}} & {{Equation}\mspace{14mu} 6}\end{matrix}$With the deflection y₀, the beam is annealed and its shape is solid andrepresents a leaf spring. So for the leaf spring, in the deflection y₀,the force is 0. While it is pressed to level state, the force will beequal to F₀. FIG. 11 shows the load F and the deflection y of the halfleaf spring. The relation between them is:F _(x) =F ₀ −f(y ₀ −y _(x))  Equation 7F_(x) and y_(x) represent the load and deflection of the leaf spring ina certain point.F _(x) =F ₀ −f(y ₀)+f(y _(x))  Equation 8AsF ₀ =f(y ₀)  Equation 9ThenF _(x) =f(y _(x))  Equation 10So for half leaf spring,

$\begin{matrix}{F = {\frac{3{EI}}{l^{3}}y}} & {{Equation}\mspace{14mu} 11}\end{matrix}$By way of example, the material of the leaf spring can be spring steel,whose elastic modulus E is 196000 MPa. And the moment of inertia of theleaf spring section I is:

$\begin{matrix}{I = \frac{{bh}^{3}}{12}} & {{Equation}\mspace{14mu} 12}\end{matrix}$where b is the width of the section and h is the thickness, as shown inFIG. 12.

In some embodiments, the at least one inner resilient member 63 can beprovided as two inner leaf springs, which equals four half leaf springs.According to the space, and the allowed moving distance, the size of theleaf spring can be designed to be: b=1 mm, h=0.2 mm, 1=6 mm (which meansan overall length of the leaf spring is 12 mm). Calculated by the aboveformula, within the allowed distance y=0.5 mm, the maximum force is0.907 N. As for two leaf springs, the whole force is (0.907*4=) 3.628 N,which is acceptable, not loading too large a force to the sensor probe55.

For the outer resilient member 53, where a single leaf spring is used,this is equal to two half leaf springs. Likewise, the size is: b=3 mm,h=0.6 mm, 1=8 mm (which means the overall length is 16 mm). Alsocalculated by the above formula, within the allowed distance y=0.1 mm,the maximum force is 6.202 N. Thus, the whole force F2 is (6.202*2=)12.404 N, which is larger than the inner force F1, and not too large forinstallation.

FIG. 13 is a schematic illustration of a switchgear 100 with at leastone onboard temperature monitoring device 10 that can be placed in atleast one location for monitoring temperature of a target contact 82. Insome embodiments, the switchgear 100 can include multiple temperaturemonitoring devices 10. The at least one device 10 can wirelesslycommunicate with at least one remote control or monitoring station 200.

FIG. 14 is a flow chart of an installation method according toembodiments of the present invention. A temperature monitoring devicewith an open center channel, a fastener assembly segment and a spacedapart temperature measuring segment is provided (block 300). The deviceis placed about a circumference of a contact of a switchgear so that thecontact extends through the open center channel (block 310). A curvedbracket of the fastener assembly can be advanced radially outward towardthe contact to align the device with an outer surface of the contact(block 320). At least one (typically a plurality) resilient member ofthe temperature measurement segment can be compressed to retract atemperature probe against a bracket while an exposed end of thetemperature probe touches the outer surface of the contact (block 330).

The device can have a primary body with ventilation gap spaces extendingangularly between 30-90 degrees between the temperature monitoringsegment and the fastener assembly segment (block 302) which can ventheat and reduce heat dissipation performance degradation.

The temperature monitoring segment can include an outer shell enclosingan inner shell holding a bracket that encloses a length of a temperaturesensor segment extending between a primary body thereof and thetemperature probe and with at least one resilient member between theouter shell and the inner shell (block 307). The compressing can includefirst translating the probe to contact an end of the bracket, thentranslating the inner and outer shells concurrently to compress an outerresilient member (block 308).

The fastener assembly segment can be diametrically opposed to thetemperature measuring segment (block 305).

The fastener assembly can include a worm gear that rotates a wheel gearthat advance the curved bracket (block 322).

The temperature monitoring segment can comprise first and secondoutwardly extending members on opposing sides of the temperature probethat touch the outer surface of the contact (block 333). These membersmay have convex curved surfaces.

The foregoing is illustrative of the present invention and is not to beconstrued as limiting thereof. Although a few exemplary embodiments ofthis invention have been described, those skilled in the art willreadily appreciate that many modifications are possible in the exemplaryembodiments without materially departing from the novel teachings andadvantages of this invention. Accordingly, all such modifications areintended to be included within the scope of this invention. Therefore,it is to be understood that the foregoing is illustrative of the presentinvention and is not to be construed as limited to the specificembodiments disclosed, and that modifications to the disclosedembodiments, as well as other embodiments, are intended to be includedwithin the scope of the invention.

That which is claimed is:
 1. A temperature monitoring device comprising:a primary body comprising an inner perimeter surrounding an openchannel; a temperature monitoring segment held by the primary body, thetemperature monitoring segment comprising a thermal probe that extendsinwardly toward the open channel; and a fastener assembly segment heldby the primary body at a location that is circumferentially spaced apartfrom the temperature monitoring segment, wherein the fastener assemblysegment comprises a circumferentially extending bracket that is radiallyextendable in a direction that is toward the open channel, and whereinthe circumferentially extending bracket has a circumferential extentthat is in a range of about 30-90 degrees.
 2. The temperature monitoringdevice of claim 1, wherein the temperature monitoring segment comprisesfir′st and second projecting members aligned with and circumferentiallyspaced apart from the thermal probe, one on each side of the thermalprobe.
 3. The temperature monitoring device of claim 1, wherein a mediallocation of the bracket of the fastener assembly segment isdiametrically opposed to the thermal probe.
 4. The temperaturemonitoring device of claim 1, wherein the temperature monitoring segmentcomprises a thermal sensor and an elongate channel, the elongate channelaligned with the thermal probe, wherein the thermal probe comprises aleg that extends in the elongate channel and that couples the thermalprobe to the thermal sensor, and wherein the thermal probe and thethermal sensor radially extend and retract as a unit relative to theinner circular perimeter of the primary body of the temperaturemonitoring device.
 5. The temperature monitoring device of claim 1,wherein the temperature monitoring segment further comprises a wirelessdigital thermal sensor coupled to or integral with the thermal probe andheld in the temperature monitoring segment.
 6. The temperaturemonitoring device of claim 1, wherein the bracket has an arcuate innersurface facing the open channel with a radius of curvature correspondingto a radius of the inner circular perimeter of the primary body of thedevice.
 7. The temperature monitoring device of claim 6, wherein thebracket comprises a threaded center channel that receives a threadedbolt.
 8. A temperature monitoring device comprising: a primary bodycomprising an inner perimeter surrounding an open channel; a temperaturemonitoring segment held by the primary body, the temperature monitoringsegment comprising a thermal probe that extends inwardly toward the openchannel, wherein the temperature monitoring segment further comprisesfirst and second projecting members, one on each side of the thermalprobe; and a fastener assembly segment held by the primary body at alocation that is circumferentially spaced apart from the temperaturemonitoring segment, wherein the fastener assembly segment comprises acircumferentially extending bracket that is radially extendable in adirection that is toward the open channel, wherein the first and secondprojecting members are at least one of flexible or comprise an elasticmaterial, and/or wherein the first and second projecting members areradially compressible in a range between 1-20% in response to a forceapplied during installation to a target contact.
 9. A temperaturemonitoring device comprising: a primary body comprising an innerperimeter surrounding an open channel; a temperature monitoring segmentheld by the primary body, the temperature monitoring segment comprisinga thermal probe that extends inwardly toward the open channel; and afastener assembly segment held by the primary body at a location that iscircumferentially spaced apart from the temperature monitoring segment,wherein the fastener assembly segment comprises a circumferentiallyextending bracket that is radially extendable in a direction that istoward the open channel, wherein the temperature monitoring segmentfurther comprises: an inner shell, the inner shell holding a digitalwireless temperature sensor that is attached to the thermal probe; anouter shell that encloses the inner shell, the outer shell comprising aradially extending bracket, wherein the radially extending bracketencloses a length of a leg of the thermal probe that extends between thetemperature sensor and the thermal probe; at least one inner resilientmember residing between the inner shell and the outer shell; and atleast one outer resilient member residing between the outer shell and anouter perimeter of the temperature monitoring device, wherein, duringinstallation and application of a force onto the thermal probe, the atleast one inner resilient member compresses so that the inner shellmoves relative to the outer shell to retract the thermal probe against adistal end of the bracket, and wherein the at least one outer resilientmember compresses when the inner and outer shell move together radiallyoutward toward the outer perimeter of the temperature monitoring device.10. The temperature monitoring device of claim 9, wherein the at leastone inner resilient member comprises first and second spaced apart leafsprings.
 11. The temperature monitoring device of claim 9, wherein theat least one outer resilient member is a single leaf spring held in ashaped cavity of a housing member of the temperature monitoring segment.12. A temperature monitoring device comprising: a primary bodycomprising an inner perimeter surrounding an open channel; a temperaturemonitoring segment held by the primary body, the temperature monitoringsegment comprising a thermal probe that extends inwardly toward the openchannel; and a fastener assembly segment held by the primary body at alocation that is circumferentially spaced apart from the temperaturemonitoring segment, wherein the fastener assembly segment comprises acircumferentially extending bracket that is radially extendable in adirection that is toward the open channel, wherein the open channel isan inner open circular channel, wherein the device further comprises anouter circular perimeter, and wherein the primary body has alongitudinal extent that is less than a longitudinal extent of thetemperature monitoring segment and the fastener assembly segment tothereby provide ventilation spaces.
 13. A temperature monitoring devicecomprising: a primary body comprising an inner perimeter surrounding anopen channel; a temperature monitoring segment held by the primary body,the temperature monitoring segment comprising a thermal probe thatextends inwardly toward the open channel; and a fastener assemblysegment held by the primary body at a location that is circumferentiallyspaced apart from the temperature monitoring segment, wherein thefastener assembly segment comprises a circumferentially extendingbracket that is radially extendable in a direction that is toward theopen channel, wherein the fastener assembly segment comprises a firstgear that cooperates with a second gear that translates the bracket. 14.The temperature monitoring device of claim 13, wherein the first gear isa worm gear and the second gear is a wheel gear, wherein the wheel gearis attached to a threaded bolt that extends into a threaded channel ofthe bracket to translate the bracket radially in response to rotation ofthe wheel gear by the worm gear.
 15. The temperature monitoring deviceof claim 14, wherein the worm gear comprises an outer facing end havinga slot for a user to access to turn the worm gear and adjust a positionof the bracket.
 16. A switchgear, comprising: at least one temperaturemonitoring device; and at least one contact that extends through an opencircular channel of a respective temperature monitoring device, whereinthe respective temperature monitoring device comprises: a primary bodycomprising an inner circular perimeter; a temperature monitoring segmentheld by the primary body, the temperature monitoring segment comprisinga thermal probe that projects out of the primary body toward the contactand is coupled to a thermal sensor in the temperature monitoringsegment, wherein the temperature monitoring segment comprises first andsecond projecting members, one on each side of the thermal probe andthat are aligned with the thermal probe, and wherein an innermost edgeof the first and second projecting members facing the contact reside atthe same radius as an innermost edge of the thermal probe facing thecontact; and a fastener assembly segment held by the primary body at alocation that is circumferentially spaced apart from the temperaturemonitoring segment, wherein the fastener assembly segment comprises acircumferentially extending bracket that is radially extendible in adirection that is toward the open channel.
 17. The switchgear of claim16, wherein the first and second projecting members have a convexlycurved surface facing the contact.
 18. The switchgear of claim 16,wherein the temperature monitoring segment further comprises: an innershell, the inner shell holding a digital wireless temperature sensorthat is attached to the probe; an outer shell that encloses the innershell, the outer shell comprising a radially extending bracket, whereinthe radially extending bracket of the outer shell encloses a length of aleg of the thermal probe that extends between the temperature sensor andthe thermal probe; at least one inner resilient member residing betweenthe inner shell and the outer shell; and at least one outer resilientmember residing between the outer shell and an outer perimeter of thetemperature monitoring device, wherein, during installation andapplication of a force onto the thermal probe, the at least one innerresilient member compresses so that the inner shell moves relative tothe outer shell to retract the probe against a distal end of the bracketof the outer shell, and wherein the at least one outer resilient membercompresses when the inner and outer shell move together radially outwardtoward the outer perimeter of the temperature monitoring device.
 19. Theswitchgear of claim 16, wherein the fastener assembly segment comprisesa worm gear attached to a wheel gear, wherein the wheel gear is attachedto a threaded bolt that extends into a threaded channel of the bracketto translate the bracket radially in response to rotation of the wheelgear by the worm gear, and wherein a medial location of the bracket ofthe fastener assembly segment is diametrically opposed to the thermalprobe.
 20. The switchgear of claim 16, wherein the circumferentiallyextending bracket extends a circumferential extent that is between 30-90degrees, and wherein the thermal probe comprises a leg that extends inan elongate channel aligned with a cavity that holds a thermal sensorand that couples the thermal probe to the thermal sensor.